#!/usr/bin/python3
import os
import re
import sys
import platform
import subprocess

from setuptools import setup, setuptools, Extension
from setuptools.command.build_ext import build_ext
from distutils.version import LooseVersion


class CMakeExtension(Extension):
    def __init__(self, name, sourcedir=''):
        Extension.__init__(self, name, sources=['./'])
        self.sourcedir = os.path.abspath(sourcedir)


class CMakeBuild(build_ext):
    def run(self):
        try:
            out = subprocess.check_output(['cmake', '--version'])
        except OSError:
            raise RuntimeError("CMake must be installed to build"
                               + " the following extensions: "
                               + ", ".join(e.name for e in self.extensions))

        if platform.system() == "Windows":
            cmake_version = LooseVersion(
                re.search(r'version\s*([\d.]+)', out.decode()).group(1))
            if cmake_version < '3.1.0':
                raise RuntimeError("CMake >= 3.1.0 is required on Windows")

        for ext in self.extensions:
            self.build_extension(ext)

    def build_extension(self, ext):
        extdir = os.path.abspath(os.path.dirname(
            self.get_ext_fullpath(ext.name))
        )
        cmake_args = ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=' + extdir,
                      '-DPYTHON_EXECUTABLE=' + sys.executable]

        cfg = 'Debug' if self.debug else 'Release'
        build_args = ['--config', cfg]

        if platform.system() == "Windows":
            cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{}={}'
                           .format(cfg.upper(), extdir)]
            if sys.maxsize > 2**32:
                cmake_args += ['-A', 'x64']
            build_args += ['--', '/m']
        else:
            cmake_args += ['-DCMAKE_BUILD_TYPE=' + cfg]
            build_args += ['--', '-j', '6']

        env = os.environ.copy()
        env['CXXFLAGS'] = '{} -DVERSION_INFO=\\"{}\\"'.format(
            env.get('CXXFLAGS', ''),
            self.distribution.get_version())
        if not os.path.exists(self.build_temp):
            os.makedirs(self.build_temp)
        subprocess.check_call(['cmake', ext.sourcedir]
                              + cmake_args, cwd=self.build_temp, env=env)
        subprocess.check_call(['cmake', '--build', '.']
                              + build_args, cwd=self.build_temp)


class get_pybind_include(object):
    """Helper class to determine the pybind11 include path

    The purpose of this class is to postpone importing pybind11
    until it is actually installed, so that the ``get_include()``
    method can be invoked. """

    def __init__(self, user=False):
        self.user = user

    def __str__(self):
        import pybind11
        return pybind11.get_include(self.user)


ext_modules = [
    Extension(
        'blspy',
        [
            'src/elements.cpp',
            'src/schemes.cpp',
            'src/privatekey.cpp',
            'src/bls.cpp',
            'python-bindings/pythonbindings.cpp',
        ],
        include_dirs=[
            # Path to pybind11 headers
            get_pybind_include(),
            get_pybind_include(user=True),
            'relic_ietf_64/include',
            'mpir_gc_x64',
            'libsodium/include',
        ],
        library_dirs=['relic_ietf_64', 'mpir_gc_x64', 'libsodium/x64/Release/v142/static'],
        libraries=['relic_s', 'Advapi32', 'mpir', 'libsodium'],
        language='c++'
    ),
]


# As of Python 3.6, CCompiler has a `has_flag` method.
# cf http://bugs.python.org/issue26689
def has_flag(compiler, flagname):
    """Return a boolean indicating whether a flag name is supported on
    the specified compiler.
    """
    import tempfile
    with tempfile.NamedTemporaryFile('w', suffix='.cpp') as f:
        f.write('int main (int argc, char **argv) { return 0; }')
        try:
            compiler.compile([f.name], extra_postargs=[flagname])
        except setuptools.distutils.errors.CompileError:
            return False
    return True


def cpp_flag(compiler):
    """Return the -std=c++[11/14/17] compiler flag.

    The newer version is prefered over c++11 (when it is available).
    """
    flags = ['-std=c++17', '-std=c++14', '-std=c++11']

    for flag in flags:
        if has_flag(compiler, flag):
            return flag

    raise RuntimeError('Unsupported compiler -- at least C++11 support '
                       'is needed!')


class BuildExt(build_ext):
    """A custom build extension for adding compiler-specific options."""
    c_opts = {
        'msvc': ['/EHsc', '/std:c++17', '/DBLSALLOC_SODIUM=1', '/DSODIUM_STATIC'],
        'unix': [],
    }
    l_opts = {
        'msvc': [],
        'unix': [],
    }

    if sys.platform == 'darwin':
        darwin_opts = ['-stdlib=libc++', '-mmacosx-version-min=10.14']
        c_opts['unix'] += darwin_opts
        l_opts['unix'] += darwin_opts

    def build_extensions(self):
        ct = self.compiler.compiler_type
        opts = self.c_opts.get(ct, [])
        link_opts = self.l_opts.get(ct, [])
        if ct == 'unix':
            opts.append('-DVERSION_INFO="%s"' % self.distribution.get_version())
            opts.append(cpp_flag(self.compiler))
            if has_flag(self.compiler, '-fvisibility=hidden'):
                opts.append('-fvisibility=hidden')
        elif ct == 'msvc':
            opts.append('/DVERSION_INFO=\\"%s\\"' % self.distribution.get_version())
        for ext in self.extensions:
            ext.extra_compile_args = opts
            ext.extra_link_args = link_opts
        build_ext.build_extensions(self)


if platform.system() == "Windows":
    setup(
        name='blspy',
        author='Mariano Sorgente',
        author_email='mariano@chia.net',
        description='BLS signatures in c++ (with python bindings)',
        long_description=open('README.md').read(),
        long_description_content_type="text/markdown",
        url="https://github.com/Chia-Network/bls-signatures",
        python_requires='>=3.7',
        setup_requires=['pybind11>=2.5.0'],
        install_requires=['pybind11>=2.5.0'],
        ext_modules=ext_modules,
        cmdclass={'build_ext': BuildExt},
        zip_safe=False,
    )
else:
    setup(
        name='blspy',
        author='Mariano Sorgente',
        author_email='mariano@chia.net',
        description='BLS signatures in c++ (python bindings)',
        python_requires='>=3.7',
        install_requires=["wheel"],
        long_description=open('README.md').read(),
        long_description_content_type="text/markdown",
        url="https://github.com/Chia-Network/bls-signatures",
        ext_modules=[CMakeExtension('blspy', '.')],
        cmdclass=dict(build_ext=CMakeBuild),
        zip_safe=False,
    )
